Motor Compressors
- Thread starter camel
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bphgravity
Senior Member
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- Florida
Re: Motor Compressors
I believe by ledger, he means nameplate?
But no, the branch circuit size can be based right off that MCA rating on the nameplate. If that rating is not provided by the manufacturer, then you can either use the RLC or the FLC as determined by the hp of the motor.
I believe by ledger, he means nameplate?
But no, the branch circuit size can be based right off that MCA rating on the nameplate. If that rating is not provided by the manufacturer, then you can either use the RLC or the FLC as determined by the hp of the motor.
dcsva@aol.com
Senior Member
- Location
- Virginia
Re: Motor Compressors
Whenever I have seen "Minimum Branch Circuit Ampacity", it was written in that little piece of paper that came "In The Box". (ie., 15Amp, 20Amp, 25Amp). IMO, This is the manufacturers recommended minimum size of the circuit breaker to be used ahead of the motor, and if you use this recommended MINIMUM value, the circuit breaker and the wire should be sized by this Amp rating.
Whenever I have seen "Minimum Branch Circuit Ampacity", it was written in that little piece of paper that came "In The Box". (ie., 15Amp, 20Amp, 25Amp). IMO, This is the manufacturers recommended minimum size of the circuit breaker to be used ahead of the motor, and if you use this recommended MINIMUM value, the circuit breaker and the wire should be sized by this Amp rating.
- Location
- Massachusetts
Re: Motor Compressors
dcsva
MCA is the minimum circuit ampacity.
The conductors can always be selected by the MCA figure even when using the larger maximum overcurrent protection figure.
A unit with a 23 amp MCA and a Maximum overcurrent protection of 40 amps could be supplied with 12 AWG copper with a 40 amp breaker.
The breaker and wire sizes are not related for motor loads.
[ February 28, 2005, 04:34 PM: Message edited by: iwire ]
dcsva
MCA is the minimum circuit ampacity.
The conductors can always be selected by the MCA figure even when using the larger maximum overcurrent protection figure.
A unit with a 23 amp MCA and a Maximum overcurrent protection of 40 amps could be supplied with 12 AWG copper with a 40 amp breaker.
The breaker and wire sizes are not related for motor loads.
[ February 28, 2005, 04:34 PM: Message edited by: iwire ]
dcsva@aol.com
Senior Member
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- Virginia
Re: Motor Compressors
Bob,
I have always been glad when your name showed in the list of people responding to a topic that I start and once again I need to listen to a voice I have come to respect. Thanks
Doug
Bob,
I have always been glad when your name showed in the list of people responding to a topic that I start and once again I need to listen to a voice I have come to respect. Thanks
Doug
Re: Motor Compressors
The nomenclature on the "rating plate" takes all the work out of this. MCA and MACP have to be followed for warranty reasons. There was a time when we weren't spoon fed this info. This is old school, but here we go: RLA+Fan= FLA
FLAx125%=MCA
FLAx175%-225%=MOCP
The nomenclature on the "rating plate" takes all the work out of this. MCA and MACP have to be followed for warranty reasons. There was a time when we weren't spoon fed this info. This is old school, but here we go: RLA+Fan= FLA
FLAx125%=MCA
FLAx175%-225%=MOCP
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